1. Field of the Invention
The invention relates in general to a light emitting diode structure, and more particularly to a light emitting diode structure capable of increasing current spreading effect.
2. Description of the Related Art
The light-emitting diode (LED) emits a light by converting electric energy into photo energy. The LED is mainly composed of semiconductors. Of the semiconductors, that having a larger ratio of holes carrying positive electricity is referred as P type semiconductor, and that having a larger ratio of electrons carrying negative electricity is referred as N type semiconductor. The junction connecting a P type semiconductor and an N type semiconductor forms a PN junction. When a voltage is applied to a positive polarity and a negative polarity of an LED chip, the electrons and the holes will be combined and then emit energy in a form of light.
In addition, the light intensity of LED is related to a current density of a voltage applied thereto. In general, the light intensity increases with the increase in the current density. However, it is not easy to increase the luminous efficiency and at the same time make the current uniformly spread. In a conventional art, the current can be uniformly spread by increasing areas of the electrodes. By doing so, the light-shading area of the electrodes would be increased and the luminous efficiency deteriorates accordingly. Conversely, if the luminous efficiency is increased by reducing the light-shading area of the electrodes, the current is crowded and cannot be spread uniformly and the effect of thermal concentration will be worsened. Therefore, how to make the current density uniformly distributed without affecting the light intensity has become a prominent task for the industries.